How often should patients on 70/30 premixed (Novolin 70/30 or Humulin 70/30) insulin be reviewed?

Review Schedule for Patients on 70/30 Premixed Insulin

Patients on 70/30 premixed insulin should be reviewed at least every 2 weeks initially when starting therapy or adjusting doses, and then can transition to monthly visits once stable glycemic control is achieved.

Initial Monitoring Period

• First 2-4 weeks: Biweekly (every 2 weeks) visits are recommended when:
  • Starting premixed insulin therapy
  • Making significant dose adjustments
  • Implementing sliding scale corrections
  • Addressing hypoglycemia concerns

This intensive monitoring schedule is supported by evidence showing that frequent clinic visits focusing on patient self-management education significantly improve glycemic control in patients using premixed 70/30 insulin 1.

Ongoing Monitoring Schedule

For Stable Patients

• Monthly visits are appropriate for patients with:
  • Stable glycemic control
  • Established injection technique
  • No recent hypoglycemic episodes
  • Consistent blood glucose patterns

For Older Adults

The American Diabetes Association recommends adjusting insulin doses every 2 weeks based on fingerstick glucose testing performed before meals 2:

• Target: 90-150 mg/dL before meals (may be adjusted based on overall health and goals of care)
• If 50% of premeal fingerstick values over 2 weeks are above goal, increase the dose
• If >2 premeal fingerstick values/week are <90 mg/dL, decrease the dose

What to Assess During Reviews

Every Visit

1. Blood glucose patterns:

   • Review patient's glucose log
   • Assess fasting and pre-meal glucose values
   • Identify patterns requiring dose adjustments

2. Injection technique and site rotation:

   • Check injection sites for lipohypertrophy (LH)
   • All patients must have their injection sites checked at every regular visit, or at least once yearly 2
   • Ensure proper rotation of injection sites to prevent LH

3. Dose adjustments:

   • Adjust doses based on blood glucose patterns
   • Increase dose by 2 units if 50% of fasting fingerstick values are above target
   • Decrease dose by 2 units if >2 fasting fingerstick values/week are <80 mg/dL 3

Quarterly Assessments

• HbA1c testing
• Comprehensive review of overall glycemic control
• Assessment of any diabetes-related complications

Special Considerations

Hypoglycemia Risk

• Patients using premixed insulin have a higher risk of hypoglycemia compared to basal-only regimens
• More frequent monitoring may be needed for:
  • Elderly patients
  • Those with hypoglycemia unawareness
  • Patients with irregular meal schedules
  • Those with renal or hepatic impairment

Timing of Administration

Remember that timing of administration is critical for premixed insulins 3:

• 70/30 NPH/regular insulin: 30 minutes before meals
• 70/30 aspart mix or 75/25 lispro mix: 0-15 minutes before meals

When to Consider Treatment Changes

If glycemic targets are not achieved despite dose optimization:

1. Consider adding non-insulin agents
2. Evaluate for transition to a more intensive insulin regimen
3. Assess for adherence issues or technique problems

Common Pitfalls to Avoid

1. Infrequent monitoring: Inadequate follow-up can lead to persistent hyperglycemia or increased hypoglycemia risk
2. Failure to check injection sites: Missing lipohypertrophy can lead to erratic insulin absorption
3. Overlooking meal timing: Premixed insulin must be coordinated with meals to avoid hypoglycemia
4. Not adjusting for lifestyle changes: Changes in activity level, diet, or weight require reassessment of insulin needs

Remember that premixed insulin regimens are not recommended for inpatient use due to high rates of iatrogenic hypoglycemia 3, so hospitalized patients may need a different insulin regimen during admission.